add analytics event to track sample downloads

Change-Id: Ibb6ca88845ca0f26b759503fbca540009e1d7c8c
diff --git a/tools/droiddoc/templates-sdk/sampleindex.cs b/tools/droiddoc/templates-sdk/sampleindex.cs
index 92985c5..98767b1 100644
--- a/tools/droiddoc/templates-sdk/sampleindex.cs
+++ b/tools/droiddoc/templates-sdk/sampleindex.cs
@@ -20,7 +20,9 @@
 &#124; Project<?cs else ?>Overview
 &#124; <a href="<?cs var:toroot ?>samples/<?cs var:projectDir ?>/project.html">Project</a>
 <?cs /if ?>
-&#124; <a href="<?cs var:toroot ?>downloads/samples/<?cs var:projectDir ?>.zip">Download</a>
+&#124; <a href="<?cs var:toroot ?>downloads/samples/<?cs var:projectDir ?>.zip"
+    onclick="_gaq.push(['_trackEvent', 'Samples', 'Download', <?cs var:projectDir ?>]);"
+    >Download</a>
 
 </div><!-- end sum-details-links -->